Assembling Parts (SDK for Java)

Updated on 2025-01-24 GMT+08:00

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Function

This API assembles the uploaded parts to compete the multipart upload. Before performing this operation, you cannot download the uploaded data. When assembling parts, you need to copy the additional message header information recorded during the multipart upload initiation to the object metadata. Such information is processed the same way the information in a common object upload is processed. In the case of assembling parts concurrently, last write wins is applied, but the time of last write is defined as the time when a multipart upload was initiated.

As long as the multipart upload is not aborted, all uploaded parts occupy the space. However, after you assembled the specified parts, those uploaded but not assembled will be deleted to free up space.

When assembling parts, OBS creates an object by putting part numbers in ascending order. If any object metadata is provided in the initiation of the multipart upload, OBS will associate the metadata with the object. After the multipart upload is complete, the parts will no longer exist. A part assembling request must contain the upload ID, part numbers, and a list of corresponding ETag values. In response to the request, the ETag that uniquely identifies the assembled parts is contained. This ETag is not the MD5 hash value of the entire object.

NOTICE:

If you have any questions during development, post them on the Issues page of GitHub.

Restrictions

To assemble parts, you must be the bucket owner or have the required permission (obs:object:PutObject in IAM or PutObject in a bucket policy). For details, see Introduction to OBS Access Control, IAM Custom Policies, and Configuring an Object Policy.
The mapping between OBS regions and endpoints must comply with what is listed in Regions and Endpoints.
After a multipart upload is complete, the uploaded parts that are not assembled will be automatically deleted and cannot be recovered. Before assembling parts, use the API for listing uploaded parts to check all parts to ensure that no part is missed.

Method

obsClient.completeMultipartUpload(CompleteMultipartUploadRequest request)

Request Parameters

**Table 1** List of request parameters
Parameter	Type	Mandatory (Yes/No)	Description
request	CompleteMultipartUploadRequest	Yes	Explanation: Request parameters for assembling parts. For details, see Table 2.

**Table 2** CompleteMultipartUploadRequest
Parameter	Type	Mandatory (Yes/No)	Description
bucketName	String	Yes	Explanation: Bucket name. Restrictions: A bucket name must be unique across all accounts and regions. A bucket name: Must be 3 to 63 characters long and start with a digit or letter. Lowercase letters, digits, hyphens (-), and periods (.) are allowed. Cannot be formatted as an IP address. Cannot start or end with a hyphen (-) or period (.). Cannot contain two consecutive periods (..), for example, my..bucket. Cannot contain periods (.) and hyphens (-) adjacent to each other, for example, my-.bucket or my.-bucket. If you repeatedly create buckets of the same name in the same region, no error will be reported and the bucket attributes comply with those set in the first creation request. Default value: None
objectKey	String	Yes	Explanation: Object name. An object is uniquely identified by an object name in a bucket. An object name is a complete path that does not contain the bucket name. For example, if the address for accessing the object is examplebucket.obs.ap-southeast-1.myhuaweicloud.com/folder/test.txt, the object name is folder/test.txt. Value range: The value must contain 1 to 1,024 characters. Default value: None
partEtag	List<PartEtag>	Yes	Explanation: List of parts to be assembled. For details, see Table 3.
uploadId	String	Yes	Explanation: Multipart upload ID, for example, 000001648453845DBB78F2340DD460D8. Value range: The value must contain 32 characters. Default value: None
encodingType	String	No	Explanation: Encoding type for objectKey in the response. If objectKey in the response contains control characters that are not supported by the XML 1.0 standard, you can specify this parameter to encode objectKey. Value range: url Default value: None. If you leave this parameter blank, encoding is not applied.
userHeaders	HashMap<String, String>	No	Explanation: User header list. In HashMap, the String key and value indicate the name and value of the user header field respectively. The SDK does not process the userHeaders and instead transparently transmits it to the server for later use. Default value: None

**Table 3** PartEtag
Parameter	Type	Mandatory (Yes/No)	Description
etag	String	Yes	Explanation: Part ETag. Base64-encoded, 128-bit MD5 value of the part. Value range: The value must contain 32 characters. Default value: None
partNumber	Integer	Yes	Explanation: Part number. Part numbers can be inconsecutive. Value range: An integer ranging from 1 to 10000. Default value: None

Responses

**Table 4** CompleteMultipartUploadResult
Parameter	Type	Description
statusCode	int	Explanation: HTTP status code. Value range: A status code is a group of digits that can be 2xx (indicating successes) or 4xx or 5xx (indicating errors). It indicates the status of a response. For more information, see Status Code. Default value: None
responseHeaders	Map<String, Object>	Explanation: Response header list, composed of tuples. In a tuple, the String key indicates the name of the header, and the Object value indicates the value of the header. Default value: None
etag	String	Explanation: Base64-encoded, 128-bit MD5 value of an object. ETag is the unique identifier of the object content. It can be used to determine whether the object content is changed. For example, if the ETag is A when an object is uploaded and is B when the object is downloaded, the object content is changed. The ETag reflects changes to the contents of the object, not its metadata. An object created by an upload or copy operation has a unique ETag. Restrictions: If an object is encrypted using server-side encryption, the ETag is not the MD5 value of the object. Value range: The value must contain 32 characters. Default value: None
bucketName	String	Explanation: Bucket in which parts are assembled. Restrictions: A bucket name must be unique across all accounts and regions. A bucket name: Must be 3 to 63 characters long and start with a digit or letter. Lowercase letters, digits, hyphens (-), and periods (.) are allowed. Cannot be formatted as an IP address. Cannot start or end with a hyphen (-) or period (.). Cannot contain two consecutive periods (..), for example, my..bucket. Cannot contain periods (.) and hyphens (-) adjacent to each other, for example, my-.bucket or my.-bucket. If you repeatedly create buckets of the same name in the same region, no error will be reported and the bucket attributes comply with those set in the first creation request. Default value: None
objectKey	String	Explanation: The name of the object the parts are assembled into. An object is uniquely identified by an object name in a bucket. An object name is a complete path that does not contain the bucket name. For example, if the address for accessing the object is examplebucket.obs.ap-southeast-1.myhuaweicloud.com/folder/test.txt, the object name is folder/test.txt. Value range: The value must contain 1 to 1,024 characters. Default value: None
location	String	Explanation: URL of the object the parts are assembled into. Example: https://example-Bucket.obs.regions.myhuaweicloud.com/example-Object. Default value: None
versionId	String	Explanation: Version ID of the object the parts are assembled into. If versioning is enabled for the bucket, the object version number will be returned. Value range: The value must contain 32 characters. Default value: None
objectUrl	String	Explanation: Full path to the object the parts are assembled into. Default value: None
encodingType	String	Explanation: Encoding type for objectKey in the response. If objectKey in the response contains control characters that are not supported by the XML 1.0 standard, you can specify this parameter to encode objectKey. Value range: url Default value: None. If you leave this parameter blank, encoding is not applied.

Code Examples

This example calls ObsClient.completeMultipartUpload to assemble parts into object objectname in bucket examplebucket based on uploadId and partEtags.

   
    
      
      import com.obs.services.ObsClient;
import com.obs.services.exception.ObsException;
import com.obs.services.model.CompleteMultipartUploadRequest;
import com.obs.services.model.PartEtag;
import java.util.ArrayList;
import java.util.List;
public class CompleteMultipartUpload001 {
    public static void main(String[] args) {
        // Obtain an AK/SK pair using environment variables or import the AK/SK pair in other ways. Using hard coding may result in leakage.
        // Obtain an AK/SK pair on the management console.
        String ak = System.getenv("ACCESS_KEY_ID");
        String sk = System.getenv("SECRET_ACCESS_KEY_ID");
        // (Optional) If you are using a temporary AK/SK pair and a security token to access OBS, you are advised not to use hard coding, which may result in information leakage.
        // Obtain an AK/SK pair and a security token using environment variables or import them in other ways.
        String securityToken = System.getenv("SECURITY_TOKEN");
        // Enter the endpoint corresponding to the bucket. CN-Hong Kong is used here as an example. Replace it with the one in your actual situation.
        String endPoint = "https://obs.ap-southeast-1.myhuaweicloud.com";
        // Obtain an endpoint using environment variables or import it in other ways.
        //String endPoint = System.getenv("ENDPOINT");
        
        // Create an ObsClient instance.
        // Use the permanent AK/SK pair to initialize the client.
        ObsClient obsClient = new ObsClient(ak, sk,endPoint);
        // Use the temporary AK/SK pair and security token to initialize the client.
        // ObsClient obsClient = new ObsClient(ak, sk, securityToken, endPoint);

        try {
            String uploadId = "upload id from initiateMultipartUpload";
            List<PartEtag> partEtags = new ArrayList<PartEtag>();
            // First part
            PartEtag part1 = new PartEtag();
            part1.setPartNumber(1);
            part1.seteTag("etag1");
            partEtags.add(part1);
            // Second part
            PartEtag part2 = new PartEtag();
            part2.setPartNumber(2);
            part2.setEtag("etag2");
            partEtags.add(part2);
            CompleteMultipartUploadRequest request =
                    new CompleteMultipartUploadRequest("examplebucket", "objectname", uploadId, partEtags);
            obsClient.completeMultipartUpload(request);
            System.out.println("completeMultipartUpload successfully");
        } catch (ObsException e) {
            System.out.println("CompleteMultipartUpload failed");
            // Request failed. Print the HTTP status code.
            System.out.println("HTTP Code:" + e.getResponseCode());
            // Request failed. Print the server-side error code.
            System.out.println("Error Code:" + e.getErrorCode());
            // Request failed. Print the error details.
            System.out.println("Error Message:" + e.getErrorMessage());
            // Request failed. Print the request ID.
            System.out.println("Request ID:" + e.getErrorRequestId());
            System.out.println("Host ID:" + e.getErrorHostId());
            e.printStackTrace();
        } catch (Exception e) {
            System.out.println("completeMultipartUpload failed");
            // Print other error information.
            e.printStackTrace();
        }
    }
}

     

   
  